What is the evolutionary biology behind breasts?

[HappyMammal]

Hi there,

I was wondering if anyone has any ideas as to why humans have permanently swollen breasts?

I understand the features men are attracted to are generally signs of fecundity, but I don't understand why humans develop larger breasts, that are permanently swollen, as opposed to only developing them when pregnant like the other members of the Great Ape family.

I understand their role as a secondary sexual characteristic, I personally find them very attractive, and I suspect a great deal of that is a social conatruct.

Anthropologist Desmond Morris suggests they increase a woman's attractiveness because cleavage reminds us what a lady looks like nude from behind, bent over.

I don't agree with that perspective, it's only fairly recent fashion that lifts and plunges such that we even get to see cleavage, we evolved before bras and plunging necklines were a thing.

I think it might have to do with reproduction in that permanently swollen breasts are part of the subterfuge of human bodies that complements the hidden ovulation of females. So essentially human females hide when they're receptive for fertilization and when they're pregnant...

Hiding their sexual status keeps males interested year round, even so humans are semi-seasonal breeders, spring does seem to bring about increased interest in mating.

I keep wanting to find a perfect, elegant answer... but every individual human is a transitional creature from what we were, to what we will be.

So the hidden ovulation byproduct is the best answer I can think of for why the permanantly swollen breasts.

[Devlyn]

I don't have any answers, but it sounds like Desmond Morris is the reason that men shouldn't bake cookies. 🤣

[Lori Dee]

So the hidden ovulation byproduct is the best answer I can think of for why the permanantly swollen breasts.

I think it is a sign that a woman is "fertile" and therefore a good match for reproduction. But it is also a product of society and less of "evolution". It has been suggested that the same effect is the reason for wearing red lipstick, as it suggests ovulation and possible sexual receptivity.

PubMed has an article entitled "The evolution of perennially enlarged breasts in women: a critical review and a novel hypothesis" that might be worth reading.